Process for the treatment of leather with india rubber



1NAN, a subject of the ALEXANDER McLENNAN, or Ross, ENGLAND.

renoonss FOR THE TREATMENT or LEATHER WITH INDIA RUBZEER.

No Drawing.

T 0 all whom it concern.

Be it known that I ALEXANDER MoLEN- King of Great Britain, residing in Ross,-= Herefordshire, England, have invented certain new and useful Improvements in Processes for the Treatment of, Leather with India Rubber, of which the following is a specification.

This invention relates to the treatment of leather with india rubber and it refers more particularly to a process such as forms the subject of United States Letters Paten granted to me under N0. 97 0,7 84.

The present invention has for its object certain improvements primarily vdesigned to secure a more perfect impregna-' tion of the leather with the rubber whereby a greater amount of rubber is forced into the leather, and its vulcanization therein, and further to provide the leather with a better gripping surface, particularly desirable when the leather is employed for the soles of boots, or machinery belting for example.

According to the present invention the leather after'having-been subjected to any necessary preliminary treatment is treated with a clarifying or grease removing solution formed by dissolving crystalline powdered sulphur in a solvent which may either be carbon bisulphide or tetrachlorethane. The liquid just referred to, which may be termed the stock solution, is allowed to stand for a time with occasional agitation after which the undissolved sulphur is precipitated by the addition, to a predetermined quantity, of the stock liquid, of a solution comprising acetone.

Instead of the above precipitants ether and benzol may be used, alone or in com 3 the leather.

bination with the foregoing.

To the mixture thus formed parafiin oil or petrol is added the resultant liquid being employed for the treatment of the leatherfor removing the grease therefrom.

The leather is then sprayed with the clarifying solution and preferably this is effected by placing the said leather in a suit able receptacle having a well fitting lild whereby when the leather has been well saturated the receptacle may be closed and evaporation as far as possible prevented. The leather after the treatment just-described is left for a certain time when it is removed and allowed to dry.

T he leather when dry is buffed upon the flesh side and is p aced in a Suitable recep- Specification'of Letters Patent. Patented Aug, 115, 1922, Application filed January 21, 1922. Serial No. 530,978. I v

tacle-which mayhave a steam or hot water acket, or other means may be provided 'whereby its contents can be heated. The

receptacle just referred to contains a solution of india rubber formed by dissolving rubber in coal tar solvent, naphtha, or benzol, which is'thinned to the desired consistency by the addition of heavy grade petroleum spirit and paraflin oil. After remaining in the solution just referred to for a certaln time the leather is removed and Worked by hand after which it is replaced in thesolution andafter a certain time is again worked by hand. With leather of a medium weight twq workings with a final immersion are usual y found sufi'icient but if found necessary a further treatment or treatments in the manner described may be given.

After its final I immersion the leather is removedand any superfluous solution is allowed to drain therefrom.

.The leather is then drummed with a rubbertsolution as just above described but of slightly greater density. a

To the solution just referred to there is added, after the drumming operation has been in progress for a certain time, a further solution of slightly greater density than that first referred to composed of the same components as the second solution. During the finalperiod of the drumming there is added at intervals solution containing gutta percha, balata, gum mastic and gum dammar, and finally about 1 hour before the conclusion of the treatment chloride of sulphur solution.

In my above mentioned patent the chloride of sulphur solution was added to the rubber solutions in the tank prior to drumming This I have found to be detrimental because it had the effect of congealing the solution thereby hindering-penetration, unless the solution be kept continually warm, which 'isdiflicult and expensive to do, and also because it was found to beinjurious to the men working the leather from the tank. A In the present instance the chloride or sulphur solution is added in the drum, at the latter end of the treatment when the leather has been thoroughly impregnated with the solutions, the required heat being obtained by the constant revolv in of the drum. In this way the desired ob ect is attained, that is avoidance of the in urlous effect upon the men and vulcanithese according to the condition or characweight are to be treated I have found that bedded in the cells of the leather by means of the process. q I

Whilst it will beunderstood that I do not desire to limit myself to the precise quanti-Q ties or proportions stated as it maybe found necessary or desirable in practice to vary Ether 18; liquid ozs. Acetone 18f liquid ozs. 'Benzol 2 1 liiquid ozst which is added to three pints of the stock solution.

Assuming that 20 to 30 hides of medium good results are obtained if the ingredients are in the following proportions I For the first rubber solution 1 lb. of india rubber is dissolved in 1 to 1% gallons of coal tar solvent, naphtha or benzol the resultant solution being thinned down with 19 to 1% gallons of petroleum spirit, preferably heavy grade, and 11} to 1%; gallons paraflin.

Or 1 lb. of india, rubber dissolved in from 22; to 24 gallons of coal tar solvent, naphtha or benzol the resultant solution being thinned down with 2 to 2%,:- gallons of arafiin.

For the fir'st drumming so ution (No. 1) 1 lb. of india rubber is dissolved in 1 to. 13, gallons of coal tar solvent, naphtha or benzol the resultant solution being thinned down with 1 to 1?; gallons petroleum spirit, preferably -heavy grade, and l to 111 gallons of araflin.

6r 1 lb. of india rubber dissolved in 1% to 2 gallons of coal tar solvent, naphtha or benzol the resultant solution being thinned down with 11} to 1% gallons of paraffin.

For the second drumming solution (No. 2). 1 lb.'of india rubber is dissolved in 1 to 13; gallons of coal tar solvent naphtha, or benzol the resultant solution being thinned down with 1- to 1 gallons petroleum spirit, preferably heavy grade, and to 1 gallon Or 1 lb. of india rubber dissolved in 14,- to 1% gallons of coal tar solvent naphtha, or

benzol, the resultant solution being thinned down with 11 to 12 gallons parafiin.

.For the gutta percha solution l lb. of gutta percha is dissolved in a solution formed of 5 to? pints of carbon bisulphide or warmed coal tar naphtha or petroleum spirit.

In the balata solution 1 lb. of balata is dis- ,seo

solved inva solution formed of 5 to 7 pints of carbon bisulphide or warmed coal tar naphtha or petroleum spirit.

The gum mastic solution is formed by dissolving 2 lbs. of gum mastic in 2 to 3 pints of benzol or other known solvents.

- ,The gum dammar solution is formed of 2 lbs. ofgum dammar dissolved i114 to 5 pints of benzol or other known solvents.

For the final treatment to one pint of the stock there is added for precipitation purposes'fi liquid ozs. of acetone or any of the other substances before mentioned as being employed as precipitants together with 6 liquid ozs. of ether, 8 liquid ozs. 'of benzol and 10 to.12 liquid ozs. of chloride of sulphur; v

The hides are first drummed for about *6 hours with 12 to 14 gallons, or more ac cording to the number of hides, of the first drumming solution, at the expiration of which 10 to 12 gallons, or more according to the number of hides, of the second drumming solution are introducedand the drum.- ming continued for a further 7 to 8 hours during which period there'are introduced at different times? the various -guml solutions and finally within one hour of the comple:

phur solution,

In practice it is found that when acetone or similar volatile liquids are employed as sulphur precipitants in the formation of the stock solution, particularly where the solution is placed in air-tight glass or other receptacles, it is difficult to keep the stoppers in the said jars whenmoving them. Under these circumstances it will be found more convenient in the final drumming to place the precipitatedstock solution in the drum, the chloride of sulphur being subsequently added, or the chloride of sulphur may be mixed with the stock solution which is then introduced into the drum, or the stock solution may be introduced into the drum and chloride of sulphur immediately thereafter.

Under these circumstances to the final treatment to 3 pints of the stock solution there is addedfor precipitation purposes 18 liquid ozs. of ether, 18 liquid ozs. of acetone, together with 24 liquid ozs. of Benzol.

The same Quantity of Chloride of sulphur will be used to each pint of the above mentioned stock solution namely 10 to 12 liquid ozs. but this will be fed into the drumseparately from the powdered sulphur solution. i

It is ob'yious to one skilled in the art that where, throughout the vspecification and claims, indiarubber is accorded the important place in the'formula and process herein, that other soluble vulcanizable gums of similar nature niabe substituted for the said india rubber, without departing from Claims. i i

1. In a process for impregnating leather with india rubber, drumming the leather in rubber solution; and when the leatheris impregnated with-the rubber adding to the rubber solution an element for vulcanizing the rubber which has become embedded in the leather.

2. In a process for impregnating leather with india rubber, drumming the leather in a revolving receptacle in rubber solution; and during a final period of the drumming adding to the rubber solution chloride of sulphur solution for vulcanizing therubber which has become embedded in the leather.

3. In a process for impregnating leather with india rubber, moving the leather in rubber solution in a movable receptacle; and when the leather is impregnated with the rubber, adding to the rubber solution an element for vnlcanizing the rubber which has become embedded in the'leather; the heat required to prevent congealing of the solution when the vulcanizing element is added being obtained by constant movement of the receptacle.

solution is added being obtained by constant movement of the l. In a process for impregnating leather with india rubber, treating the leather for impregnating .the leatherwith rubber; and when the leather is impregnated-with the rubber treating the leather with an element for vulcanizing the rubber which has become embedded in the leather.

receptacle.

In testimony whereof I have hereunto set my hand in the presence of two witnesses. ALEXANDER MoLEN N AN.

Witnesses:

ERNEST MARTIN BERRY, CHARLES WILLIAM PHILLIPS.

moving the leather in 

